Analytical studies on amplitude change enhancement in coupled aluminium nitride coated single crystal silicon oscillator pair applicable to ultra-sensitive resonating microfluidic flowmeters

The use of vibration mode localisation in arrays of micromechanically coupled, nearly identical beam-shaped resonators has been analytically studied for ultra-sensitive resonating-based flowmeters. Eigenstate shifts (amplitude change in this Letter) that are about two times (compared with the single resonator), and orders (compared with the resonator array) of magnitude greater than corresponding shifts in resonant frequency for an induced fluid flow (corresponding to an induced small mass perturbation) are preliminarily obtained by theoretical analysis. When an external force of 100 Pa, corresponding to an estimated fluid flow velocity of about 3.15 m/s, is applied to any one (because of the symmetrical design) of the two coupled aluminium nitride coated single crystal silicon resonators, two orders of the amplitude enhancement can be observed for both the resonators at the higher (second) resonance frequency because of vibration mode localisation, which implies the application possibility to highly sensitive resonating-based flow sensors.